1. Field of the Invention
This invention relates to a filter module. More particularly, this invention relates to a filter module having a module housing, and at least one filter element. Even more particularly, this invention relates to a filter module having at least on inlet opening, at least one filtrate outlet and the module housing having at least one joint line.
2. Description of the Prior Art
Filter modules are known from process technology. They are used in many ways. U.S. Pat. No. 4,368,119 shows an apparatus for filtering a liquid, for example. U.S. Pat. No. 4,849,104 shows another apparatus filter module. Especially filter modules which work according to the membrane separation method are used in the treatment of water, in desalination of sea water and briny water, in the foodstuff industry, in the pharmaceutical and electric industries to separate a component from a liquid or a gas. Filter modules comprise a number of rod-like filter elements when configured according to the principle of tube modules which are arranged parallel with respect to each other. Groups of such filter elements are usually combined and clamped at the ends by means of tops in the module housing. The tops extend perpendicular to the rods and are provided with a number of bores corresponding to the number of filter elements. The internal space of the filter elements is sealed off at the ends with respect to the internal space of the module housing. The medium to be filtered is introduced into the filter elements, the permeate passes through the membrane layer of the filter elements and the residue remains in the filter element or is discharged again via an outlet.
Due to the large range of applications of the filter modules, different requirements are placed on the materials both of the filter elements as well as the module housing parts and the tops. Frequently, the application of a surface coating is necessary in the filter module housing or the tops in order to protect the suspension from impurities on the one hand and to protect the housing parts and the tops from corrosion on the other hand.
Due to the fact that especially the internal surfaces of the filter module housing need to be coated, the application of the coating is difficult and unsatisfactory, especially frequently in the area of the interior face sides.